As is known to those skilled technicians in the art, fluid compressors, and especially fluid compressors used in refrigeration systems comprise (among many other functional components) suction acoustic filters and discharge acoustic filter.
In general, said acoustic filters comprise volumetric chambers arranged within the compressor hermetic housing, between the output and input of the compression cylinder and the inlet or outlet pipe of the compressor hermetic housing.
The function and the functional principle of the acoustic filters are longtime known to the technicians skilled in the subject matter. It's knows, therefore, that said acoustic filters—suction or discharge filters—aim to reduce the noise caused by the functional pulse of the compressor.
One major difference between a discharge acoustic filter and a suction acoustic filter, in hermetic compressors, consists of the fact that the discharge acoustic filter has the volume thereof isolated from the inner environment of the hermetic housing of the compressor, while the suction acoustic filter has the input thereof in constant fluid communication with the interior of the compressor hermetic housing.
It means that a discharge acoustic filter is directly connected—via specific pipes—to the compression cylinder, inside the hermetic housing, and to the cooling line, outside the compressor housing.
Therefore, there is no important problem regarding the constructiveness of the in let and/or out let connections and/or joints of acoustic filters. This is because they have the inlets and/or outlets thereof welded to the pipes.
The same does not occur with a suction acoustic filter, after all, this is directly connected only to the compression cylinder, the other end thereof (or pipe) arranged within the hermetic housing, and it may or may not be connected to the suction line of the cooling system, and usually there is no such direct connection. This is because it is preferred that the entire volume of the compressor hermetic housing is equalized with the pressure of said suction line of the cooling system.
Therefore, there is a special care with the outlet pipe of the suction acoustic filters of hermetic compressors. In this sense, one can observe that the current state of the art provides fundamentally special constructions for pipes of suction acoustic filters.
Document U.S. Pat. No. 6,280,153 describes, for example, an outlet pipe of a suction acoustic filter-pipe connected to the compression cylinder of the hermetic compressor—the constructivity thereof in steps aims to minimize the contact edges which may represent barriers to the suction flow.
Document WO2005075828 also describes, for example, an outlet pipe of a suction acoustic filter—pipe connected to the compression cylinder of the hermetic compressor—the constructivity there of in duplicate aims to provide fluid flow to two suction valves.
It is also known a constructivity of suction acoustic filter where the inlet pipe—pipe free of connection and freely arranged inside the hermetic compressor housing—has two suction holes. This embodiment is relatively conventional, and it can best be seen in FIG. 1.
As can be assessed by observing FIG. 1, two suction holes are provided in a same suction inlet pipe of a suction acoustic filter. The main objective of the embodiment illustrated in FIG. 1 is to obtain, from the smallest possible dimensions (a single suction pipe) the greater possible suction capacity (double inlet).
However, the greater suction capacity of the embodiment illustrated in FIG. 1 is proportional to the diameter of the single pipe, rather than the number of inlet holes. Moreover, the fluid flow sucked by one of the holes can also impair the fluid flow sucked by the other hole.
Thus, the present utility model patent arises based on the general perspective (where it is noted a concerned with the outlet pipe greater than with the inlet pipe of the suction acoustic filters of hermetic compressors).